Fluorinated amphoteric surfactants

Amphoteric fluorinated surfactants are bifunctional compounds which can function both as anionic and as cationic surfactants, depending on the pH of the medium [87]. Amphoteric surfactants have at least one cationic group and at least... 

Amphoteric fluorinated surfactants usually have a (1) carboxybetaine (I), (2) sulfobetaine (II), or (3) sulfatobetaine (III) structure ... 

Examples of amphoteric fluorinated surfactants are given in Table 1.6. 

Trianion-type amphoteric fluorinated surfactants C8Fi7C0NH(CH2)3N+(C2H4OH)(CH2COOH)2CH2COO 102... 

The perfluoroalkylethanesulfonyl chlorides are useful intermediates for producing cationic and amphoteric fluorinated surfactants. 

Reaction of the amine with /3-propiolactone instead of methyl iodide yields the corresponding amphoteric fluorinated surfactant, of the structure CioFi90C6H4S02NHCH2CH2N+(CH3)2CH2CH2COO . 

Amphoteric fluorinated surfactants have at least one anionic and at least one cationic group at about their isoelectric point [181]. The cationic group is usually a quaternary amine or a protonated tertiary or secondary amine. The anionic functionality is a carboxylate, sulfonate, sulfate, or phosphate group. Most widely used fluorinated surfactants are carboxybetaine-type amphoteric surfactants which have, like betaines, a cationic amine functionality and an anionic carboxylate group. Instead of a carboxylate group, the anionic component of sulfatobetaines is a sulfate group and that of sulfobetaines is a sulfonate group. 

The synthetic methods utilized for the preparation of amphoteric fluorinated surfactants are similar to those used for cationic surfactants, except for the alkylation step. A tertiary amine can be prepared by reaction of a fluorinated ester or acid halide with a diamine which contains both a primary or a secondary amine and a tertiary amine [195]. The resulting amine is then treated with chloroacetic acid ... 

Oligomerization of tetrafluoroethylene provides intermediates for amphoteric fluorinated surfactants. The tetrafluoroethylene pentamer reacts with phenol to form a phenyl ether [96]. Chlorosulfonation of the phenyl ether with chlorosul-fonic acid yields a sulfonyl chloride, which is allowed to react with A dimethyl-propanediamine ... 

A reaction of the resulting tertiary amine with /3-propiolactone gives an amphoteric fluorinated surfactant ... 

Amphoteric fluorinated surfactants with heterocyclic nitrogen have been prepared by treating a fluorinated ester with A/-(2-hydroxyethyl)piperazine and subsequently with chloroacetic acid [195] ... 

Perfluoroalkyl esters react with cyclic A -aminoquatemary salts to give an amphoteric fluorinated surfactant with a heterocyclic nitrogen [201] ... 

Amphoteric fluorinated surfactants with heterocyclic nitrogen have also been prepared by the Michael addition of 2-perfluoroalkylethanethiol to either a maleic monoamide or monoester [163,202-204] ... 

Anionic, nonionic, or amphoteric fluorinated surfactants prevent fogging of glass [12-14] and plastic cover sheets used in agriculture. Potassium perfluorooc-... 

Cationic or amphoteric fluorinated surfactants can impart a positive charge to fluoropolymer particles and aid electroplating of the polymer (e.g., PTFE) onto steel for surface protection [104]. A nonionic fluorinated surfactant (Forafac FI 110) is a leveling agent for zinc electrodeposition [105]. 

An AFFF agent for extinguishing or preventing fires has been formulated with a mixture of an amphoteric fluorinated surfactant, A -[(dimethy-lamino)propyl]-2(or 3)-(l,l,2,2-tetrahydroperfluoroaIkylthio)succinamic acid, an anionic fluorinated surfactant, perfluoroalkanoic acid, and an ionic and a nonionic nonfluorinated surfactant [151]. 

Fluorinated surfactants usually differ widely in their foaming power (see Section 4.9). Cationic fluorinated surfactants and amphoteric fluorinated surfactants (e.g., Zonyl FSK) are foaming agents in aqueous media. On the other hand, nonionics (e.g., Zonyl FSN and Zonyl FSO) are low-foaming surfactants [1]. Endcapping reduces foaming. 

Anionic, cationic, or amphoteric fluorinated surfactants with a hydroxyl group on the a-carbon improve foam stability [163]. 

An amphoteric fluorinated surfactant in silicone rubber sealants makes the seal soil resistant [283]. An anionic fluorinated surfactant prevents leakage of mineral oil around nitrile rubber seals [284]. 

Evaporation of hydrocarbon fuel (e.g., gasoline) can be prevented with an aqueous layer containing anionic or amphoteric fluorinated surfactants [328,329]. Fluorinated surfactants are effective because of their low surface tension. 

An amphoteric fluorinated surfactant, Du Font s Zonyl FSB, has been used as a calibration standard for high-resolution FAB-MS measurements [94],... 

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